1. Field of the Invention
The present invention generally relates to methods and apparatus for making and breaking wellbore tubulars. More particularly, the present invention relates to apparatus and methods for a makeup and breakout system for use on a rig floor that integrates functions including cleaning and doping the threads of the tubular, spinning the connection, wrenching the connection, guiding the stabbing process, and handling mud spillage.
2. Description of the Related Art
Hydrocarbon wells typically begin by drilling a borehole from the earth's surface to a selected depth in order to intersect a hydrocarbon bearing formation. While the depth of a typical borehole reaches several thousand feet, the length of an individual drill pipe is only approximately thirty feet. Therefore, in the construction of oil or gas wells it is usually necessary to assemble long strings of drill pipe. Due to the length of these pipes, sections or stands of pipe are progressively added to the pipe as it is lowered into the well from a drilling platform. In particular, when it is desired to add a section or stand of pipe the string is usually restrained from falling into the well by applying the slips of a spider located in the floor of the drilling platform. The new section or stand of pipe is then moved from a rack to the well center above the spider. The threaded pin of the section or stand of pipe to be connected is then located over the threaded box of the pipe extending from the well and the connection is made up by rotation therebetween. An elevator is connected to the top of the new section or stand and the entire pipe string lifted slightly to enable the slips of the spider to be released. The entire pipe string is then lowered until the top of the section is adjacent the spider whereupon the slips of the spider are re-applied, the elevator disconnected and the process repeated. Removing the drill pipe from the well requires disassembling the long string of drill pipe by the same process as assembly except in reverse order. When breaking the connection between the pipes as they come out of the well, fluid or mud from within the top drill pipe typically spills out. Without a means of containing and collecting the mud, safety risks increase, replacing lost mud raises costs, and environmental issues become present.
Completion and production phases of oil or gas wells require similar connections between other tubulars such as casing, liner, and tubing. In general, the diameter, location, and function of the tubular that is placed in the wellbore determines whether it is known as drill pipe, casing, liner, or tubing. However, the general term tubular or tubing encompasses all of the applications.
It is common practice to use devices designed to aid and automate making up and breaking out the drill pipe. Tools used in this process include devices for cleaning and doping the threads, spinners that quickly rotate the pipes, hydraulic power tongs or wrenches that torque the connection, stabbing guides that align the pipes, and mud buckets that contain mud spillage. Currently, these devices represent substantially non-integrated separate tools with different levels of automation. Therefore, the process of assembling and disassembling drill pipe strings requires manual operation of controls and a high level of physical interaction within close proximity of the tool being used at the well center. This provides both a risk of injury and a higher possibility of incorrect operation of the various devices while making up and breaking out the drill pipe. The monotonous routine of these operations increases the probability of injury and operator error. Therefore, a tool offering remote operation and substantial automation reduces safety risks and increases repeatability due to the limited human interaction that is necessary.
In addition, individual devices used in making up and breaking out drill pipe inefficiently occupy a large amount of space on the drilling platform. These devices must compete for space with tools used in other operations on the platform. Due to limited floor space on drilling platforms, leasing or obtaining additional floor space for the individual devices becomes expensive. Acquiring additional floor space on an off-shore rig floor is especially expensive since this may require obtaining an extra boat with a deck that can be positioned near the platform and used for transferring tools onto and off of the rig floor. Therefore, an integrated tool for making and breaking pipe connections that utilizes a small footprint offers substantial cost savings in the construction of oil and gas wells.
When utilizing independent devices in making up and breaking out drill pipe, a separate mechanism must be used within each device that centers and positions the pipe into proper alignment. This introduces a redundancy in mechanisms used to center and position the drill pipe. Independent and non-integrated devices also lack the ability to utilize one control system. Due to the high costs associated with the construction of oil and gas wells, time is critical, and repeating the drill pipe positioning operations and arranging independent components over the well at the appropriate time increases the time taken to attach each new section or stand of pipe. Positioning independent components around the drill pipe at the appropriate time requires the use of interlocking structures that prevent collisions between the individual tools. Traditionally, individual devices cost more than single integrated devices, especially when the integrated device incorporates common features of the individual devices.
Therefore, there is a need for an improved apparatus for making or breaking a tubular connection. Further, there is a need for an apparatus that will make up or break out a tubular connection that combines and integrates individual tools into one space efficient, safe, precise, remote controlled operation.